The convergence of advances in the fields of networking, wireless communications, mobile computing, and the Internet, has made it technologically feasible to provide virtually any type of information and/or services to individuals at virtually anytime and any place. It is envisioned that small, unobtrusive devices can be set up to transmit specific information regarding an object, business, or point of reference associated with that particular device. These devices serve as “information access points” (IAP's) for providing specific, localized information. A passerby, can access this information by pointing his or her personal communications device, such as a cell phone, personal digital assistant, or any type of mobile computing device, at the IAP device and download the transmitted information.
For example, a painting at a museum could have an associated IAP device which continuously broadcasts information regarding that painting. A visitor to the museum who is interested in that painting, could then direct his or her portable communications device at the IAP device to receive textual, audio, and/or visual information regarding that painting. Alternatively, the IAP device could provide the visitor with a URL or some type of pointer to a web site which has the desired information. Furthermore, that person may be interested in finding where other paintings by that same artist may be found in the museum. This would require that the IAP devices have known physical locations (e.g., latitude and longitude). It would be of great benefit were most, if not all, IAP devices to have known locations. An individual could then be directed to the nearest restaurant, restroom, bus stop, hospital, newstand, ATM machine, pay phone, etc., by virtue of the IAP devices.
There exist many different ways by which to establish an IAP device's location. One method entails utilizing traditional surveying techniques to fix the location of an IAP device. Unfortunately, this method is quite time consuming and expensive. As such, traditional surveying techniques are typically limited to known landmarks or to locations of significance. It would be cost prohibitive to survey in each and every one of the multitudes of IAP devices. Another method entails using the Global Positioning System (GPS) to establish the locations of IAP devices. However, GPS generally requires a direct line-of-sight to several of the orbiting satellites. Consequently, GPS cannot be used to establish the locations of indoor IAP devices. Another commonly used technique involves cellular triangulation. Unfortunately, cellular triangulation has limited accuracy (e.g., 100 meters for standard cell sizes and less than 25 meters for microcells). Furthermore, cellular triangulation is susceptible to multi-pathing problems indoors.
Thus, there exists a need for a quick, cost-efficient, and accurate method for automatically determining the location of an IAP device. It would be highly preferable if such an apparatus or method works equally well indoors as well as outdoors. The present invention provides one unique, novel solution to these problems.